Field of the Invention
The present invention relates to a display device and a method for manufacturing the same, and more particularly, to a display device having a window or touch screen detachably attached thereto and a method for manufacturing the same.
Background of the Related Art
A display device forms a screen through a display like a liquid crystal display LCD, an organic light-emitting diode OLED, and an electronic paper display EPD. The display device is applied to all kinds of video screen devices. On the other hand, the display device is provided with a touch screen so as to improve the conveniences in manipulation. Further, a window, which is made of tempered glass or transparent polymer resin, is disposed on the front surface of the touch screen. The window is divided into a display portion and a bezel portion along which edges are printed, thereby protecting the display device from the damages caused by external impacts or contacts. The window is attached fixedly to the touch screen by means of an OCA (Optical Clear Adhesive) or ultraviolet curing adhesive. Recently, a flexible and bent display has been introduced so that a window corresponding to the display appears.
FIGS. 1 and 2 are schematic sectional views showing representative examples of conventional display devices in which touch screens are adopted. At this time, the display devices include bent devices as well as flat devices as shown.
As shown in FIGS. 1 and 2, the conventional display devices are configured wherein a touch screen 2 and a window 3 are laminated sequentially on a display 1 like an LCD or OLED. An adhesive layer 4 is formed on both of the space between the display 1 and the touch screen 2 and the space between the touch screen 2 and the window 3 (See FIG. 1). Otherwise, as shown in FIG. 2, the touch screen 2 and the window 3 are attached to each other by means of the adhesive layer 4. The display device as shown in FIG. 2 has a conductive pattern (not shown) of the touch screen 2 formed on the display 1. The conventional window 3 has a high hardness, and among the whole parts of the display device, the window 3 has a relatively high price.
The conventional display device manufactured through the adhesion has the following problems. Firstly, if the window 3 or the touch screen 2 is damaged, it is difficult to exchange it with new one. Especially, an operation for exchanging the window 3 or the touch screen 2 in the display device is frequently conducted. So as to conduct the exchanging operation, first, the damaged window 3 or touch screen 2 is removed from the display device. Next, a new window 3 or touch screen 2 is manufactured, and so as to allow the new window 3 or touch screen 2 to be attached to the new touch screen 2 or the display 1, an adhesive is applied to any one surface of the new window 3 or touch screen 2. This operation cannot be conducted at all by a consumer.
Further, the adhesive layer 4 has the adhesion strength of more than about 1,000 gf/25 mm, and typically, it has the adhesion strength of more than 1,500 gf/25 mm. Further, the adhesive layer 4 generally has a thickness in the range of 10 to 200 μm. It is hard for the consumer to remove the adhesive from the window 3 or the touch screen 2, without having any remaining materials thereon. Accordingly, the exchanging operation for the damaged window 3 or touch screen 2 should be conducted in a place where the exchanging equipment exists. If the consumer contacts a service center of the manufacturing company of the display device and thus sends the damaged display device to the service center, the damaged window 3 or touch screen 2 is exchanged with new one through the service center having the exchanging equipment, and thus, the repaired display device is sent back to the consumer. Therefore, the damaged window 3 or touch screen 2 cannot be easily exchanged by the consumer, and a relatively long period of time is needed to complete the exchanging of the display device.
Secondly, it is not easy to recycle the display device due to the existence of the adhesive layer 4. Recently, it becomes important to recycle the display device. So as to recycle the display device, the window 3 or the touch screen 2 has to be separated from the display device. For such separation, the display device is heated to soften the adhesive layer 4, and next, the window 3 or the touch screen 2 is separated from the display device by means of a wire. Otherwise, the display device is momentarily cooled by means of liquid nitrogen, and then, the window 3 or the touch screen 2 is separated from the display device. So as to recycle the display device, that is, additional cost and time for separating the window 3 or the touch screen 2 from the display device are required, which is not economical.
Thirdly, an adhesion process with no air bubbles is needed in manufacturing the conventional display devices. If there are no air bubbles, a refraction ratio and a reflection ratio are minimized, thereby improving the luminance of the display device. A process for removing the air bubbles becomes complicated by means of the adhesive layer 4. In more detail, the adhesive layer 4 is formed uniformly by means of injection, and next, air bubbles are removed from the adhesive layer 4 by means of close contact and pressure reduction. After that, the adhesive layer 4 is cured through ultraviolet rays. The adhesive layer 4 has to have no air bubbles, and accordingly, the formation of the adhesive layer 4 is conducted very precisely. Therefore, the conventional display devices are manufactured with relatively high-priced manufacturing equipment, thereby raising the manufacturing cost thereof. Furthermore, adhesion with air bubbles often occurs in the conventional display devices, thereby also raising a failure rate.
Lastly, the conventional display devices do not satisfy the consumer's desires to obtain various and excellent designs in shapes, colors and patterns. A variety of products, complicated manufacturing process, and high manufacturing cost become obstacles to the satisfaction of the consumer's desires. Further, if the display device is manufactured with various designs, after services for the respective designs should be conducted one by one by the manufacturing company of the display device. In conventional practices, accordingly, the window 3 is designed only with a single color like black and white.